As to the question,
which came first,the Chicken or the Egg?the egg has
existed on Earth for at least several hundred million years,while the Hen has been here only fifty million years.

And the difference between them, is the difference between
mortalityand immortality. 1

An egg does not die a natural
death.The egg's single cell continually divides,and grows
into a multicelled organism.

For most animals, however, the process of death and dying is inevitable.

We know
that sexual reproduction –the mixing of two different sets of
chromosomes –leads to programmed cell death in an offspring,
and ultimately to the demise of the adult.

As
microbiologist extraordinaireLynn Margulis likes to remind us:death is a sexually transmitted disease.

One consequence of
programmed cell death is population control. If it were not for the
inevitability of death, the population of a species could easily
inflate to a critical size, leading to an increased competition for
resources, and under extreme circumstances, to the elimination
of the entire species.

Barring a random accident, the Egg
will continue to persist without the threat of death or
dying.

While the Chicken, on the other hand, must
ultimately sacrifice itself for the survival of the species as
a whole.

2.

In direct contrast, it
is possible that proteins may have evolvedprior to DNA
molecules. 2

Proteins are the structural building blocks of an
organism, while DNA is typically located inside the nucleus.

If you think of the nucleus as the embryo or egg,and proteins as
its protecting membrane,or material body,

then one may
concludethat the chicken, did in fact, come before the egg.